DE102018106690B4 - evaporation mask substrate, evaporation mask substrate manufacturing process, evaporation mask manufacturing process and display device manufacturing process - Google Patents

Abstract

A vapor deposition mask substrate (1), which is a metal foil having the shape of a strip and designed to be etched to have a plurality of holes (32H) and used to make a vapor deposition mask, the metal foil having a longitudinal direction ( DL) and a width direction (DW), the metal foil has shapes in the width direction (DW) taken from different positions in the longitudinal direction (DL) of the metal foil and different from each other, each shape has waves that are in the width direction (DW) repeat, each wave has a valley at each of two ends of the wave, each wave has a length, which is a length of a straight line in the width direction (DW) connecting one of the valleys of the wave to the other valley, a Percentage of a height of each wave based on the length of the wave is a unit steepness, the metal foil has a unit length in the longitudinal direction (DL) of 500 mm, a maximum value of the unit steepnesses of the metal foil for the unit length is a first steepness, and the first steepness is less than or equal to 0 .5% is.

Description

background

The invention relates to a vapor deposition mask substrate, a method of manufacturing a vapor deposition mask substrate, a method of manufacturing a vapor deposition mask and a method of manufacturing a display device.

A vapor deposition mask substrate has a first surface, a second surface, and holes extending through the first and second surfaces. The first surface faces a target, such as a substrate, and the second surface is opposite the first surface. The holes each have a first opening located in the first surface and a second opening located in the second surface. The vapor deposition material entering the holes through the second openings forms a pattern on the target that corresponds to the position and shape of the first openings (see for example JP 2015 - 055 007 A ).

Each hole of the vapor deposition mask has a cross-sectional area that increases from the first opening to the second opening. This increases the amount of deposition material entering the hole through the second opening so that the first opening reaches a sufficient amount of deposition material. However, at least some of the vapor deposition material that enters the hole through the second opening adheres to the wall surface defining the hole and therefore cannot reach the first opening. The evaporation material adhered to the wall surface may prevent other evaporation material from passing through the hole, lowering the dimensional accuracy of the pattern.

In order to reduce the volume of evaporation material adhered to the wall surfaces, a structure has been considered in which the thickness of the evaporation mask is reduced to reduce the areas of the wall surfaces. In order to reduce the thickness of the vapor deposition mask, a technique has been considered that reduces the thickness of the metal foil used as the substrate for manufacturing the vapor deposition mask.

However, in the process of etching the metal foil to form holes, a smaller thickness of the metal foil results in a smaller volume of metal that must be removed. This limits the allowable ranges in processing conditions, such as the time during which an etchant is supplied to the metal foil and the temperature of the etchant supplied. This increases the difficulty of achieving the required dimensional accuracy of the first and second openings. The production of the metal foil includes, in particular, a rolling step in which the base material is drawn with rollers, or an electrolysis step in which the metal foil, which is deposited on an electrode, is detached from the electrode. The metal foil accordingly has a wavy shape. For the metal foil having such a shape, the duration during which the ridges in the corrugated shape are in contact with the etchant is very different from that of the valleys in the corrugated shape. This exacerbates the lower accuracy resulting from the limited allowable ranges described above. Although a thinner evaporation mask as such reduces the amount of evaporation material adhered to the wall surfaces and thereby increases the dimensional accuracy of the patterns upon repeated evaporation, such a evaporation mask has another problem that the required dimensional accuracy of the pattern is difficult to achieve with each evaporation .

To stabilize the transport, US 2016/0 208 392 A1 proposes a metal foil with a corrugated shape, which has a wave surrounded by two valleys in the width direction in a central part and two slopes in the areas next to the central part, the end points of which are above go out the top of the wave.

Brief description of the invention

It is an object of the invention to provide a vapor deposition mask substrate, a method of manufacturing a vapor deposition mask substrate, a method of manufacturing a vapor deposition mask and a method of manufacturing a display device which increase the accuracy of patterns formed upon vapor deposition.

According to one embodiment of the invention, there is provided a vapor deposition mask substrate which is a metal foil having the shape of a strip and adapted to be etched to form a plurality of holes and to be used to make a vapor deposition mask. The metal foil has a longitudinal direction and a width direction. The metal foil has shapes in the width direction taken at different positions in the longitudinal direction of the metal foil and different from each other. Each shape has waves that repeat in the widthwise direction. Each wave has a valley at each of two ends of the wave. Each wave has a length, which is a length of a straight line in the latitudinal direction connecting one of the troughs of the wave to the other trough. A percentage of a height of each wave relative to the length of the wave is a unit steepness. The metal foil has a unit length in the longitudinal direction of 500 mm. A maximum value of the unit slopes of the metal foil for the unit length is a first slope. The first slope is less than or equal to 0.5%.

According to another embodiment of the invention, a method for producing a vapor deposition mask substrate is provided. The vapor deposition mask substrate is a metal foil that has the shape of a strip and is designed to be etched to have a plurality of holes and used to make a vapor deposition mask. The method includes obtaining the metal foil by rolling a base material. The metal foil has a longitudinal direction and a width direction. The metal foil has shapes in the width direction taken at different positions in the longitudinal direction of the metal foil and different from each other. Each shape has waves that repeat in the widthwise direction. Each wave has a valley at each of two ends of the wave. Each wave has a length, which is a length of a straight line in the latitudinal direction connecting one of the troughs of the wave to the other trough. A percentage of a height of each wave relative to the length of the wave is a unit steepness. The metal foil has a unit length in the longitudinal direction of 500 mm. A maximum value of the unit slopes of the metal foil for the unit length is a first slope. The base material is rolled in such a way that the first steepness is less than or equal to 0.5%.

According to a further embodiment of the invention, a method for producing a vapor deposition mask is provided. The method includes forming a resist layer on a metal foil having the shape of a strip and, using the resist layer as a mask, forming a plurality of holes in the metal foil by etching to form a mask portion. The metal foil has a longitudinal direction and a width direction. The metal foil has shapes in the width direction taken at different positions in the longitudinal direction of the metal foil and different from each other. Each shape has waves that repeat in the widthwise direction. Each wave has a valley at each of two ends of the wave. Each wave has a length, which is a length of a straight line in the latitudinal direction connecting one of the valleys of the wave to the other valley. A percentage of a height of each wave relative to the length of the wave is a unit steepness. The metal foil has a unit length in the longitudinal direction of 500 mm. A maximum value of the unit slopes of the metal foil for the unit length is a first slope. The first slope is less than or equal to 0.5%.

According to yet another embodiment of the invention, a method for producing a display device is provided. The method includes preparing a vapor deposition mask manufactured by the method for producing a vapor deposition mask described above, and forming a pattern by vapor deposition using the vapor deposition mask.

Brief description of the drawings

• 1 ist eine Perspektivansicht, die ein Aufdampfmaskensubstrat zeigt.
• 2 ist eine Draufsicht, die ein Messsubstrat zeigt.
• 3 ist ein Schaubild, das eine Kurve zur Darstellung einer Steilheit zusammen mit dem Querschnittaufbau eines Messsubstrats zeigt.
• 4 ist eine Draufsicht, die den planaren Aufbau einer Maskeneinrichtung zeigt.
• 5 ist eine Teilschnittansicht, die ein Beispiel des Querschnittaufbaus eines Maskenabschnitts zeigt.
• 6 ist eine Teilschnittansicht, die ein anderes Beispiel des Querschnittaufbaus eines Maskenabschnitts zeigt.
• 7 ist eine Teilschnittansicht, die ein Beispiel des Verbindungsaufbaus zwischen einer Kante eines Maskenabschnitts und einem Rahmenabschnitt zeigt.
• 8 ist eine Teilschnittansicht, die ein anderes Beispiel des Verbindungsaufbaus zwischen einer Kante eines Maskenabschnitts und einem Rahmenabschnitt zeigt.
• 9(a) ist eine Draufsicht, die ein Beispiel des planaren Aufbaus einer Aufdampfmaske zeigt.
• 9(b) ist eine Schnittansicht, die ein Beispiel des Querschnittaufbaus der Aufdampfmaske zeigt.
• 10(a) ist eine Draufsicht, die ein anderes Beispiel des planaren Aufbaus einer Aufdampfmaske zeigt.
• 10(b) ist eine Schnittansicht, die ein anderes Beispiel des Querschnittaufbaus der Aufdampfmaske zeigt.
• 11 ist ein Prozessbild, das einen Walzschritt zur Herstellung eines Aufdampfmaskensubstrats zeigt.
• 12 ist ein Prozessbild, das einen Heizschritt zur Herstellung eines Aufdampfmaskensubstrats zeigt.
• 13 bis 18 sind Prozessbilder, die einen Ätzschritt zur Herstellung eines Maskenabschnitts zeigen.
• 19(a) bis 19(h) sind Prozessbilder zur Darstellung eines Beispiels eines Verfahrens zum Herstellen einer Aufdampfmaske.
• 20(a) bis 20(e) sind Prozessbilder zur Darstellung eines Beispiels eines Verfahrens zur Herstellung einer Aufdampfmaske.
• 21(a) bis 21(f) sind Prozessbilder zur Darstellung eines Beispiels eines Verfahrens zur Herstellung einer Aufdampfmaske.
• 22 ist eine Draufsicht, die den planaren Aufbau eines Messsubstrats eines Beispiels zusammen mit Abmessungen zeigt.

The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The invention, along with its objects and advantages, may best be understood in conjunction with the accompanying drawings from the following description of the presently preferred embodiments.

• 1 is a perspective view showing a vapor deposition mask substrate.
• 2 is a top view showing a measurement substrate.
• 3 is a diagram showing a curve to represent a slope along with the cross-sectional structure of a measurement substrate.
• 4 is a top view showing the planar structure of a mask device.
• 5 is a partial sectional view showing an example of the cross-sectional structure of a mask portion.
• 6 is a partial sectional view showing another example of the cross-sectional structure of a mask portion.
• 7 is a partial sectional view showing an example of the connection structure between an edge of a mask portion and a frame portion.
• 8th is a partial sectional view showing another example of the connection structure between an edge of a mask portion and a frame portion.
• 9(a) is a top view showing an example of the planar structure of a vapor deposition mask.
• 9(b) is a sectional view showing an example of the cross-sectional structure of the vapor deposition mask.
• 10(a) is a top view showing another example of the planar structure of a vapor deposition mask.
• 10(b) is a sectional view showing another example of the cross-sectional structure of the vapor deposition mask.
• 11 is a process image showing a rolling step for producing a deposition mask substrate.
• 12 is a process image showing a heating step for producing a vapor deposition mask substrate.
• 13 until 18 are process images that show an etching step to produce a mask section.
• 19(a) until 19(h) are process images to illustrate an example of a method for producing a vapor deposition mask.
• 20(a) until 20(s) are process images to illustrate an example of a process for producing a vapor deposition mask.
• 21(a) until 21(f) are process images to illustrate an example of a process for producing a vapor deposition mask.
• 22 is a top view showing the planar structure of a measurement substrate of an example along with dimensions.

Detailed description of the preferred embodiments

With reference to 1 until 22 Embodiments of a vapor deposition mask substrate, a method for producing a vapor deposition mask substrate, a method for producing a vapor deposition mask and a method for producing a display device will now be described.

- Structure of vapor deposition mask substrate -

As in 1 As shown, a vapor deposition mask substrate 1 is a metal foil having the shape of a strip. The vapor deposition mask substrate 1 has a wavy shape in which waves repeat in the width direction DW at each of different positions in the length direction DL. The wavy shapes at the various positions in the longitudinal direction DL of the vapor deposition mask substrate 1 are different from each other. The various corrugated shapes differ in characteristics such as the number of corrugations (projections and depressions), the wavelength and the height of the corrugations in the corrugated shapes. For illustration purposes, the shapes of the vapor deposition mask substrate 1 are 1 in 1 exaggerated. The thickness of the vapor deposition mask substrate 1 is between 10 μm and 50 μm. The thickness uniformity of the vapor deposition mask substrate 1 is such that the ratio of the difference between the maximum thickness and the minimum thickness to the average thickness is less than or equal to 5%, for example.

The vapor deposition mask substrate 1 may consist of nickel or a nickel-iron alloy, such as a nickel-iron alloy that contains at least 30% by mass of nickel. The vapor deposition mask substrate 1 can in particular consist of Invar, which consists mainly of an alloy containing 36% by mass of nickel and 64% by mass of iron. If the main component is the alloy of 36 mass% nickel and 64 mass% iron, the rest contains additives such as chromium, manganese, carbon and cobalt. When the evaporation mask substrate 1 is made of Invar, the evaporation mask substrate 1 has a thermal expansion coefficient of about 1.2 × 10 ^-6 /°C. The vapor deposition mask substrate 1 having such a thermal expansion coefficient produces a mask that changes size due to thermal expansion to an extent equivalent to that of a glass substrate and a polyimide film. A glass substrate or a polyimide film is therefore suitably used as the vapor deposition target.

- steepness -

When the vapor deposition mask substrate 1 is placed on a flat surface, the position (height) of the surface of the vapor deposition mask substrate 1 with respect to the flat surface is referred to as the surface position.

To measure the surface position, a metal foil made by rolling or electrolysis is cut such that the dimension of the metal foil is 2 with respect to the width direction DW, a width is W. Then, the vapor deposition mask substrate 1, which is a metal foil having the shape of a strip, is wound up to form a roll. Then, a longitudinal cutting step occurs in which the vapor deposition mask substrate 1 is cut transversely in the width direction DW (along the width), so that a measurement substrate 2M is cut out as a portion of the vapor deposition mask substrate 1 in the longitudinal direction DL. The width W in the width direction DW of the measurement substrate 2M is equal to the dimension in the width direction DW of the vapor deposition mask substrate 1. Then, at various positions in the width direction DW and at predetermined intervals in the longitudinal direction DL, the surface position of the surface 2S of the measurement substrate 2M is measured. The area in which the surface position is measured is a measuring area ZL.

The measuring range ZL is a range that excludes the non-measuring ranges ZE located on the two edges in the longitudinal direction DL of the measuring substrate 2M. The measurement area ZL also excludes the non-measurement areas (not shown) located on the two edges in the width direction DW of the measurement substrate 2M. The longitudinal cutting step of cutting the vapor deposition mask substrate 1 can give the measurement substrate a new corrugated shape different from the corrugated shape of the vapor deposition mask substrate 1. The length in the longitudinal direction DL of each non-measuring area ZE corresponds to the area in which such a new corrugated shape can be formed, and the non-measuring areas ZE are excluded from the measurement of the surface position. The length in the longitudinal direction DL of each non-measuring area ZE is, for example, 100 mm. In order to exclude the new wavy shape formed at the edges in the width direction DW in the slitting step, each of the non-measuring areas at the edges in the width direction DW has a dimension of, for example, 10 mm in the width direction DW from the edge.

3 is a curve showing an example of the surface position at various positions in the width direction DW of the measurement substrate 2M, together with the cross-sectional structure of a cut taken in the width direction DW of the measurement substrate 2M. 3 shows an example of one of the different cuts in the longitudinal direction DL. This cut has three waves in the width direction DW.

As in 3 As shown, the various positions in the width direction DW at which the surface positions are measured are set at intervals that enable the corrugated shape of the vapor deposition mask substrate 1 to be displayed. The various positions in the width direction DW at which the surface positions are measured are, for example, at intervals between 1 mm and 20 mm in the width direction DW. The line LC connecting the surface positions at the various positions in the width direction DW is regarded as a line running along the surface of the vapor deposition mask substrate 1. The length of the line LC is the distance along the surface of the vapor deposition mask substrate 1. The waves in the line LC each have a length L1, L2 or L3, which is the length of the straight line connecting one of the valleys of the wave in the width direction with the other connects. The waves in line LC each have a height HW1, HW2 or HW3, which is the height of the straight line connecting one of the troughs of the wave to the other. The percentage of the height of a wave based on the length of the wave is a unit steepness of the vapor deposition mask substrate 1. In the example in 3 the unit steepnesses are the height HW1/length L1 × 100 (%), the height HW2/length L2 × 100 (%) and the height HW3/length L3 × 100 (%). If the peak of a wave in the width direction DW is on an edge, the length in the width direction DW of the wave is estimated to be twice the length from the peak to the valley of the wave.

The vapor deposition mask substrate 1 has a unit length in the longitudinal direction DL of 500 mm.

The evaporation mask substrate 1 has a first slope, which is the maximum value of the unit slopes of all waves in a portion in the evaporation mask substrate 1 having the unit length and the width W.

The vapor deposition mask substrate 1 also has a second steepness, which is the maximum value of the unit steepnesses of all the waves in the width direction DW, at a position in the longitudinal direction DL. That is, the first slope of the vapor deposition mask substrate 1 is the maximum value of the second slopes for the unit length.

The number of waves in the width direction DW at a position in the length direction DL of the vapor deposition mask substrate 1 is referred to as a wave amount at that position.

The first steepness of the vapor deposition mask substrate 1 satisfies condition 1 below. As for the steepnesses in the width direction DW of the vapor deposition mask substrate 1, it is preferable that the second steepnesses satisfy the condition 2 and the wave amounts satisfy the conditions 3 and 4.

Condition 1: The first slope is less than or equal to 0.5%.

Condition 2: The average of the second slopes is less than or equal to 0.25%.

Condition 3: The maximum value of the wave sets for the unit length is less than or equal to four.

Condition 4: The mean value of the wave sets for the unit length is less than or equal to two.

In the vapor deposition mask substrate 1 satisfying the condition 1, the maximum value of the unit slopes, which are the slopes in the width direction DW, is less than or equal to 0.5%. Accordingly, the vapor deposition mask substrate 1 is without a wave having a steep projection or a steep depression when viewed in the longitudinal direction DL. A steep projection or depression tends to cause stagnation of the liquid supplied to the projection or depression. For example, the presence or absence of such a wave cannot be easily determined from the average of the unit slopes. Therefore, when the liquid for processing is supplied to the surface of the vapor deposition mask substrate 1 which is conveyed in the longitudinal direction DL, the liquid will not stall around the protruding waves. This promotes the uniform flow of liquid on the surface of the vapor mask substrate 1 even when the same process is repeated in the longitudinal direction DL. Accordingly, the liquid supplied to the surface of the vapor mask substrate is unlikely to flow in a portion in the longitudinal direction DL comes to a halt. This increases the uniformity of the processing, which includes the treatment in the longitudinal direction DL by means of a liquid such as an etchant, that is, the uniformity of the holes in the vapor deposition mask substrate 1 in the longitudinal direction DL. This in turn increases the accuracy of the pattern formed by vapor deposition.

In addition, during roll processing in which the vapor deposition mask substrate 1 is pulled out of a roll and then forwarded, the tension that pulls the vapor deposition mask substrate 1 acts in the longitudinal direction DL of the vapor deposition mask substrate 1. The tension that acts in the longitudinal direction DL stretches the bulge and the depressions in the vapor deposition mask substrate 1 in the longitudinal direction DL. This pull initially acts on the section of the vapor deposition mask substrate 1 that is currently being pulled out of the roll. In this section, a larger steepness in the latitudinal direction DW increases the variation in the stretch ratios. Each time the reel rotates, the time at which the pull is likely to cause a stretch and the time at which the pull is unlikely to cause a stretch are repeated. This leads to problems such as deviations in transfer and wrinkles of the vapor deposition mask substrate 1 transferred in the longitudinal direction DL. As such, during roll processing, larger steepnesses in the width direction DW tend to cause deviations in routing. In addition, when another layer, such as a dry film resist, is applied to the deposition mask substrate 1, larger steepnesses tend to cause problems such as misalignment and lower adhesion due to wrinkles. The structure that satisfies Condition 1 limits transmission deviations, misalignment and wrinkles, thereby improving the accuracy of the patterns formed by vapor deposition.

The liquid supplied to the surface of the vapor mask substrate 1 may be a developing solution for developing the resist layer on the surface of the vapor mask substrate 1 and a cleaning solution for removing the developing solution from the surface. The liquid supplied to the surface of the evaporation mask substrate 1 may also be an etchant for etching the evaporation mask substrate 1 and a cleaning solution for removing the etchant from the surface. Furthermore, the liquid supplied to the surface of the vapor deposition mask substrate 1 may be a A stripping solution for stripping the resist layer remaining on the surface of the vapor mask substrate 1 after etching, and a cleaning solution for removing the stripping solution from the surface.

The structure described above, in which the flow of liquid supplied to the surface of the vapor mask substrate 1 is unlikely to stall in the longitudinal direction DL, increases the uniformity of processing on the surface of the vapor mask substrate 1 by means of the liquid. In addition, the structure in which the average value of the second steepness satisfies Condition 2 limits the unit steepness over the entire length in the longitudinal direction DL, which further increases the accuracy of the patterns. Furthermore, this structure improves the adhesion between the vapor deposition mask substrate 1 conveyed in the longitudinal direction DL and the resist layer such as a dry film and the accuracy of contact with the resist layer. Therefore, the structure that satisfies conditions 1 and 2, in addition to limiting the stoppage of the liquid flow in the longitudinal direction DL, improves the accuracy of the contact. This further improves the uniformity of the machining.

In addition, in the vapor deposition mask substrate 1 satisfying condition 3, the maximum value of the unit length wave quantities is less than or equal to four. Accordingly, the vapor deposition mask substrate 1 does not have many waves when viewed in the longitudinal direction DL. Therefore, when liquid is supplied for processing to the surface of the vapor deposition mask substrate 1 that is conveyed in the longitudinal direction DL, the liquid will not stall, which would happen if a portion in the longitudinal direction DL had a large amount of waves. This promotes the uniform flow of liquid on the surface of the vapor deposition mask substrate 1 even when the same process is repeated in the longitudinal direction DL.

Furthermore, in the vapor deposition mask substrate 1 satisfying the condition 4, the average value of the wave quantities for the unit length is less than or equal to two, so that the number of waves is not large over the entire length in the longitudinal direction DL. Accordingly, this structure further improves the adhesion between the vapor deposition mask substrate 1 conveyed in the longitudinal direction DL and the resist layer such as the dry film, and increases the accuracy of contact with the resist layer.

The structure satisfying the conditions 1 to 4 and the advantages of this structure as such are attainable only when the problem in surface processing by means of the liquid occurring in the evaporation mask substrate 1 which is passed in the longitudinal direction DL and also the problem associated with the effect of the tension acting in the longitudinal direction DL can be recognized.

- Setting up the mask device -

4 shows schematically the planar structure of a mask device, which includes a vapor deposition mask that was produced using the vapor deposition mask substrate 1. 5 shows an example of the cross-sectional structure of a mask section of a vapor deposition mask. 6 shows another example of the cross-sectional structure of a mask section of a vapor deposition mask. The number of vapor deposition masks in the mask device and the number of mask sections in a vapor deposition mask 30 are only shown as examples.

As in 4 As shown, a mask device 10 includes a main frame 20 and three vapor deposition masks 30. The main frame 20 has the shape of a rectangular frame and supports the vapor deposition masks 30. The main frame 20 is attached to a vapor deposition device that performs vapor deposition. The main frame 20 has main frame holes 21 that extend through the main frame 20 and extend over substantially the entire areas in which the vapor deposition masks 30 are placed.

The vapor deposition masks 30 have a plurality of frame sections 31 each having the shape of a planar strip, and three mask sections 32 in each frame section 31. Each frame section 31, which supports mask sections 32 and has the shape of a planar strip, is attached to the main frame 20. Each frame section 31 includes frame holes 33 that extend through the frame section 31 and extend over substantially the entire areas in which the mask sections 32 are placed. The frame portion 31 has higher rigidity than the mask portions 32 and is shaped as a frame surrounding the frame holes 33. The mask portions 32 are separately attached by welding or gluing to frame inner edge portions of the frame portion 31 that define the frame holes 33.

As in 5 As shown, an example of a mask portion 32 consists of a mask plate 323. The mask plate 323 may be a single planar element consisting of a vapor deposition mask substrate 1 or a stack of a single planar element consisting of a vapor deposition mask substrate 1 and a plastic film . 5 shows a single planar element consisting of the vapor deposition mask substrate 1.

The mask plate 323 has a first surface 321 (the underside in 5 ) and a second surface 322 (the top in 5 ), which is opposite to the first surface 321. The first surface 321 faces the vapor deposition target, such as a glass substrate, when the mask device 10 is attached to a vapor deposition device. The second surface 322 faces the vapor deposition source of the vapor deposition device. The mask portion 32 has a plurality of holes 32H extending through the mask plate 323. The wall surface defining each hole 32H is inclined with respect to the thickness direction of the mask plate 323 in a sectional view. In a sectional view, the wall surface defining each hole 32H may be a semicircular shape protruding from the hole 32H, as shown in 5 is shown, or have a complex curved shape with a multitude of bend points.

The mask plate 323 has a thickness between 1 µm and 50 µm, preferably between 2 µm and 20 µm. A thickness of the mask plate 323 that is less than or equal to 50 μm allows the holes 32H formed in the mask plate 323 to have a depth of less than or equal to 50 μm. This thin mask plate 323 allows the wall surfaces defining the holes 32H to have small areas, thereby reducing the volume of flash material adhered to the wall surfaces defining the holes 32H.

The second surface 322 has second openings H2, which are openings of the holes 32H. The first surface 321 has first openings H1, which are openings of the holes 32H. The second openings H2 are larger in plan view than the first openings H1. Each mask hole 32H is a passage for the exhaust particles sublimated from the exhaust source. The exhaust material sublimated from the exhaust source moves from the second openings H2 to the first openings H1. The second openings H2, which are larger than the first openings H1, increase the amount of flash material entering the holes 32H through the second openings H2. The area of each hole 32H in a cross section along the first surface 321 may increase monotonically from the first opening H1 toward the second opening H2, or may be substantially uniform in a portion between the first opening H1 and the second opening H2.

As in 6 As shown, another example of a mask portion 32 includes a plurality of holes 32H extending through the mask plate 323. The second openings H2 are larger than the first openings H1 in a plan view. Each hole 32H is composed of a large hole 32LH having a second opening H2 and a small hole 32SH having a first opening H1. The large hole 32LH has a cross-sectional area that monotonically decreases from the second opening H2 to the first surface 321. The small hole 32SH has a cross-sectional area that monotonically decreases from the first opening H1 to the second surface 322. The portion of the wall surface defining each hole 32H where the large hole 32LH meets the small hole 32SH at a central portion in the thickness direction of the mask plate 323 protrudes into the inside of the hole 32H. The distance between the first surface 321 and the protruding portion of the wall surface defining the hole 32H is a step height SH. The example of in 5 The cross-sectional structure shown has zero step height SH. In order to increase the amount of vapor deposition material reaching the first openings H1, the step height SH is preferably zero. In order for a mask portion 32 to have zero step height SH, the mask plate 323 should be thin enough so that the formation of the holes 32H is achieved by wet etching from only one side of the vapor deposition mask substrate 1. For example, the mask plate 323 may have a thickness of less than or equal to 50 μm.

- Mask section connection setup -

7 shows an example of the cross-sectional structure of a connection between a mask section 32 and a frame section 31. 8th shows another example of the cross-sectional structure of a connection between a mask section 32 and a frame section 31.

In the example in 7 As shown, the outer edge portion 32E of a mask plate 323 is a region free of holes 32H. The part of the second surface 322 of the mask plate 323 included in the outer edge portion 32E of the mask plate 323 is an example of a side surface of the mask ken section and is connected to the frame section 31. The frame portion 31 has inner edge portions 31E that define frame holes 33. Each inner edge portion 31E has a connecting surface 311 (the bottom in 7 ), facing the mask plate 323, and a non-connection surface 312 (the top in 7 ), which is opposite to the connecting surface 311. The thickness T31 of the inner edge portion 31E, that is, the distance between the connecting surface 311 and the non-connecting surface 312, is sufficiently larger than the thickness T32 of the mask plate 323, which allows the frame portion 31 to have a higher rigidity than the mask plate 323. The frame section 31 has a high rigidity, which in particular limits sagging of the inner edge section 31E due to its own weight and an offset of the inner edge section 31E to the mask section 32. The connecting surface 311 of the inner edge portion 31E has a connecting portion 32BN connected to the second surface 322.

The connecting portion 32BN runs continuously or intermittently along substantially the entire circumference of the inner edge portion 31E. The connection portion 32BN may be a weld mark formed by welding the connection surface 311 of the second surface 322 or a connection layer that connects the connection surface 311 to the second surface 322. When the connecting surface 311 of the inner edge portion 31E is connected to the second surface 322 of the mask plate 323, the frame portion 31 applies a tension F to the mask plate 323, which pulls the mask plate 323 outward.

The main frame 20 also applies a tension to the frame section 31, which pulls the frame section 31 outwards. This voltage corresponds to the voltage F applied to the mask plate 323. Accordingly, the vapor deposition mask 30 removed from the main frame 20 is relieved of the stress caused by the connection between the main frame 20 and the frame portion 31, and the stress F applied to the mask plate 323 is released. The position of the connecting portion 32BN in the connecting surface 311 is preferably adjusted such that the voltage F acts isotropically on the mask plate 323. Such a position can be selected according to the shape of the mask plate 323 and the shape of the frame holes 33.

The connection surface 311 is a plane that includes the connection portion 32BN and extends from the outer edge portion 32E of the second surface 322 to the outside of the mask plate 323. In other words, the inner edge portion 31E has a planar structure that extends the second surface 322 somewhat outwardly, so that the inner edge portion 31E extends from the outer edge portion 32E of the second surface 322 to the outside of the mask plate 323. In the area where the connecting surface 311 extends, a space V corresponding to the thickness of the mask plate 323 is likely to be formed around the mask plate 323. This limits physical interference between the vapor deposition target S and the frame portion 31 around the mask plate 323.

8th shows another example in which the outer edge portion 32E of the second surface 322 has an area free of holes 32H. The outer edge portion 32E of the second surface 322 has a connection portion 32BN by means of which the outer edge portion 32E is connected to the connection surface 311 of the frame portion 31. The frame portion 31 applies a tension F to the mask plate 323, which pulls the mask plate 323 outward. The frame section 31 also creates a space V corresponding to the thickness of the mask plate 323 in the area in which the connecting surface 311 extends.

The mask plate 323, which is not subjected to the voltage F, may have some waves similar to the evaporation mask substrate 1. The mask plate 323, which is exposed to the voltage F, i.e. the mask plate 323 mounted on the vapor deposition mask 30, can deform in such a way that the heights of the waves are lower. However, no deformation caused by the stress F exceeds the allowable degree when the vapor deposition mask substrate 1 satisfies the above-described conditions. Accordingly, the holes 32H in the vapor deposition mask 30 are less likely to deform, improving the accuracy of the position and shape of the patterns.

- Amount of mask sections -

9(a) and 9(b) show an example of the relationship between the amount of holes 32H in a vapor deposition mask 30 and the amount of holes 32H in a mask portion 32. 10(a) and 10(b) show another example of the relationship between the amount of holes 32H in a vapor deposition mask 30 and the amount of holes 32H in a mask portion 32.

9(a) shows an example in which the frame portion 31 has three frame holes 33 (33A, 33B and 33C). As in 9(b) As shown, the vapor deposition mask 30 of this example has a mask portion 32 (32A, 32B or 32C) in each of the frame holes 33. The inner edge portion 31E defining the frame hole 33A is connected to one mask portion 32A, the inner edge portion 31E defining the frame hole 33B is connected to another mask portion 32B, and the inner edge portion 31E defining the frame hole 33C is connected to the other Mask section 32C connected.

The evaporation mask 30 is repeatedly used for a variety of evaporation targets. Thus, the position and structure of the holes 32H in the vapor deposition mask 30 must be highly accurate. If the position and configuration of the holes 32H do not have the desired accuracy, replacement of the mask portions 32 or repair of the vapor deposition mask 30 may be required during manufacture.

For example, when only one of the mask portions 32 needs to be replaced, the structure in which the amount of holes 32H prescribed in a frame portion 31 requires as shown in FIG 9(a) and 9(b) is divided into three mask sections 32, only the replacement of one of the three mask sections 32. In other words, two of the three mask sections 32 can continue to be used. Thus, the structure in which the mask portions 32 are separately connected to the respective frame holes 33 reduces the consumption of various materials involved in manufacturing and repair of the vapor deposition mask 30. In addition, a thinner mask plate 323 and smaller holes 32H tend to reduce the Yield of the mask portion 32 and increase the need for replacement of the mask portion 32. Accordingly, the structure in which each frame hole 33 has a mask portion 32 is particularly suitable for a vapor deposition mask 30 requiring high resolution.

The position and structure of the holes 32H are preferably determined while the voltage F is being applied, that is, while the mask sections 32 are connected to the frame section 31. In this regard, the connecting portion 32BN preferably extends in parts and discontinuously along the inner edge portion 31E so that the mask portion 32 is replaceable.

10(a) shows an example in which the frame portion 31 has three frame holes 33 (33A, 33B and 33C). As in the example of 10(b) As shown, the vapor deposition mask 30 may include a mask portion 32 common to the frame holes 33. The inner edge portion 31E defining the frame hole 33A, the inner edge portion 31E defining the frame hole 33B, and the inner edge portion 31E defining the frame hole 33C are connected to the common mask portion 32. The structure in which the amount of holes 32H prescribed in a frame portion 31 is allocated to a single mask portion 32 includes only one mask portion 32 connected to the frame portion 31. This reduces the load required for the connection between the frame portion 31 and the mask portions 32. In addition, a thicker mask plate 323 forming the mask portion 32 and larger holes 32H tend to increase the yield of the mask portion 32 and reduce the need for replacement of the mask portion 32. Thus, the structure in which the frame holes 33 share the common mask portion 32 is , particularly suitable for a vapor deposition mask 30, which requires a low resolution.

- Method for producing a vapor deposition mask substrate -

Methods for producing the vapor deposition mask substrate will now be described. As a method for producing a vapor deposition mask substrate, a method using rolling and a method using electrolysis are separately described. The process using rolling is described first, followed by the process using electrolysis. 11 and 12 show an example that uses rollers.

Regarding 11 the process using rolling prepares a base material 1a made of, for example, Invar. The base material 1a extends in the longitudinal direction DL. Then, the base material 1a is forwarded to a rolling mill 50 such that the longitudinal direction DL of the base material 1a is parallel to the direction in which the base material 1a is forwarded. The rolling mill 50 may include a pair of rolls 51 and 52 that roll the base material 1a. This stretches the base material 1a in the longitudinal direction DL, thereby forming a rolled material 1b. The rolled material 1b is cut, so that it has a width W in the width direction DW. The rolled material 1b may be wound around a core C or handled in a state of running in the form of a strip. The rolled material 1b has a thickness between, for example, 10 μm and 50 μm inclusive. 11 shows an example in which a single pair of rollers is used, but multiple pairs of rollers can also be used.

As in 12 is shown, the rolled material 1b is then passed on to an annealing device 53. The annealing device 53 heats the rolled material 1b stretched in the longitudinal direction DL. This removes the residual stress remaining in the rolled material 1b and forms the deposition mask substrate 1. The pressing force between the rollers 51 and 52, the rotation speed of the rollers 51 and 52, and the annealing temperature of the rolled material 1b are adjusted so that condition 1 is satisfied. Preferably, parameters such as the pressing force between the rollers 51 and 52, the rotation speed of the rollers 51 and 52, the pressing temperature of the rollers 51 and 52 and the annealing temperature of the rolled material 1b are adjusted so that in addition to condition 1, conditions 2 to 4 are satisfied . The rolled material 1b can be cut after the annealing process to have the width W in the width direction DW.

In the method using electrolysis, the vapor deposition mask substrate 1 is formed on the surface of the electrode for electrolysis and then removed from the surface. An electrolysis drum electrode that has a highly polished surface and is immersed in the electrolysis bath and another electrode that supports the electrolysis drum electrode from the bottom and faces the surface of the electrolysis drum electrode can be used. An electric current flows between the electrolysis drum electrode and the other electrode, and the vapor deposition mask substrate 1 is deposited on the electrode surface, which is the surface of the electrolysis drum electrode. When the evaporation mask substrate 1 on the rotating electrolysis drum electrode reaches the desired thickness, the evaporation mask substrate 1 is peeled off from the surface of the electrolysis drum electrode and wound into a roll.

When the vapor deposition mask substrate 1 is made of Invar, the electrolysis bath for electrolysis contains, for example, an iron ion source, a nickel ion source, and a pH buffer. The electrolysis bath used for electrolysis may also contain a stress reliever, an Fe ³⁺ ion sequestering agent and a complexing agent such as malic acid and citric acid, and is a weakly acidic solution with a pH adjusted for electrolysis. Examples of the iron ion source include ferrous sulfate heptahydrate, ferrous chloride and ferrous sulfamate. Examples of the nickel ion source include nickel (II) sulfate, nickel (II) chloride, nickel sulfamate and nickel bromide. Examples of the pH buffer include boric acid and malonic acid. Malonic acid also serves as an Fe ³⁺ ion sequestering agent. The stress reliever can be, for example, sodium saccharin. The electrolysis bath used for electrolysis may be an aqueous solution containing the above-mentioned additives and adjusted by means of a pH adjusting agent such as 5% sulfuric acid or nickel carbonate to have a pH between, for example, 2 and including 3 has. If necessary, an annealing step can be included.

As conditions for electrolysis, the temperature of the electrolysis bath, the current density and the electrolysis time are set according to the properties of the vapor deposition mask substrate 1, such as the thickness and the composition ratio. The anode used in the electrolysis bath can be made of pure iron and nickel. The cathode used in the electrolysis bath can be a stainless steel plate such as SUS304. The temperature of the electrolysis bath can be between 40°C and 60°C. The current density can be between 1 A/dm ² and 4 A/dm ² . The current density on the surface of the electrode is adjusted so that condition 1 is satisfied. Preferably, the current density on the surface of the electrode is adjusted so that, in addition to condition 1, conditions 2 to 4 are met.

The evaporation mask substrate 1 made by electrolysis and the evaporation mask substrate 1 made by rolling may be further thinned by chemical or electric polishing. The polishing solution used for chemical polishing may be a chemical polishing solution for an iron alloy containing hydrogen peroxide as a main component. The electrolyte used for electric polishing is a perchloric acid-based electropolishing solution or a sulfuric acid-based electropolishing solution. Since the above-described conditions are satisfied, the surface of the vapor deposition mask substrate 1 has only a limited fluctuation due to polishing by the polishing solution and due to cleaning of the polishing solution by a cleaning solution.

- Method for producing a mask section -

With reference to 13 until 18 is now a process for producing the in 6 mask section 32 shown. The process of making the in 5 The mask portion 32 shown is the same as the process for manufacturing the mask portion 32 shown in FIG 6 mask section 32 shown. The overlapping steps are not described.

Referring to 13 The production of a mask portion begins with the preparation of a vapor deposition mask substrate 1 having a first surface 1Sa and a second surface 1Sb, a first dry film resist 2 (a first TFR 2) to be attached to the first surface 1Sa, and a second dry film resist 3 ( a second TFR 3) to be attached to the second surface 1Sb. The TFRs 2 and 3 are formed separately from the vapor deposition mask substrate 1. Then, the first TFR 2 is attached to the first surface 1Sa and the second TFR 3 is attached to the second surface 1Sb. Since the conditions described above are satisfied, the attachment of the TFRs 2 and 3, which are passed along the vapor deposition mask substrate 1, to the vapor deposition mask substrate 1, which is passed in the longitudinal direction DL, is less likely to cause deviations in the transfer Misalignment or wrinkling results.

Referring to 14 The portions of the TFRs 2 and 3 other than the portions in which the holes are to be formed are exposed, and the TFRs are then developed. This forms the first through holes 2a in the first TFR 2 and the second through holes 3a in the second TFR 3. The development of the exposed TFRs uses, for example, a sodium carbonate solution as the development solution. Since the above-described conditions are satisfied, the surface of the vapor mask substrate 1 has a limited fluctuation due to development by the developing solution and cleaning by a cleaning solution. Additionally, the attachment process is unlikely to result in routing variations, misalignment, or wrinkles, thereby limiting associated exposure position offset and increasing exposure accuracy. This increases the uniformity of the shape and size of the first and second through holes 2a and 3a in the surface of the vapor deposition mask substrate 1.

As in 15 As shown, the first surface 1Sa of the vapor deposition mask substrate 1 can be etched with a ferric chloride solution using the developed first TFR 2 as a mask. A second protective layer 61 is formed over the second surface 1Sb, so that the second surface 1Sb is not etched together with the first surface 1Sa. The second protective layer 61 can consist of a material that is chemically resistant to the iron (III) chloride solution. In this way, small holes 32SH extending to the second surface 1Sb are formed in the first surface 1Sa. Each small hole 32SH has a first opening H1 opening in the first surface 1Sa. Since the above-described conditions are satisfied, the surface of the vapor deposition mask substrate 1 has a limited fluctuation due to etching by an etchant and cleaning by a cleaning solution. This increases the uniformity of the shape and size of the small holes 32SH in the surface of the vapor deposition mask substrate 1.

The etchant for etching the vapor deposition mask substrate 1 may be an acidic etchant. When the vapor deposition mask substrate 1 is made of Invar, an etchant capable of etching Invar may be used. The acidic etchant may be a solution containing perchloric acid, hydrochloric acid, sulfuric acid, formic acid or acetic acid mixed in iron (III) perchlorate solution, or a mixture of an iron (III) perchlorate solution and an iron (III) chloride -Be a solution. The evaporation mask substrate 1 can be etched by a dipping method that immerses the evaporation mask substrate 1 in an acidic etchant, or by a spraying method that sprays an acidic etchant onto the evaporation mask substrate 1.

Referring to 16 The first TFR 2 formed on the first surface 1Sa and the second protective layer 61 on the second TFR 3 are removed. In addition, a first protective layer 4 is formed on the first surface 1Sa to prevent additional etching of the first surface 1Sa. The first protective layer 4 can consist of a material that chemically withstands the iron (III) chloride solution.

As in 17 As shown, the second surface 1Sb is then etched with ferric chloride solution using the developed second TFR 3 as a mask. Large holes 32LH extending to the first surface 1Sa are thus formed in the second surface 1Sb. Each large hole 32LH has a second opening H2 opening in the first surface 1Sb. The second openings H2 are larger than the first openings H1 in a top view of the second surface 1Sb. Since the above-described conditions are satisfied, the surface of the vapor deposition mask substrate 1 has a limited fluctuation due to etching by an etchant and due to cleaning of the etchant by a cleaning solution. This increases the uniformity of the shape and size of the large holes 32LH in the surface of the vapor deposition mask substrate 1. The etchant used in this step may also be an acidic etchant. When the vapor deposition mask substrate 1 is made of Invar, an etchant capable of etching Invar may be used. The evaporation mask substrate 1 can also be etched by a dipping method that immerses the evaporation mask substrate 1 in an acidic etchant, or by a spraying method that sprays an acidic etchant onto the evaporation mask substrate 1.

As in 18 As shown, removing the first protective layer 4 and the second TFR 3 from the vapor deposition mask substrate 1 provides the mask portion 32 having a plurality of small holes 32SH and large holes 32LH connected to the small holes 32SH.

In the manufacturing method using rolling, the vapor deposition mask substrate 1 has a certain amount of a metal oxide such as aluminum oxide or magnesium oxide. Namely, a deoxidizing agent such as granular aluminum or magnesium is typically mixed into the material to prevent mixing of oxygen into the base material 1a when the base material 1a is formed. The aluminum or magnesium remains in the base material 1a to a certain extent as metal oxide such as aluminum oxide or magnesium oxide. In this regard, the manufacturing method using electrolysis limits the mixing of the metal oxide into the mask portion 32.

- Method for producing a vapor deposition mask -

Various examples of a method for producing a vapor deposition mask will now be described. With reference to 19(a) until 19(h) An example of a method of forming holes by wet etching (the first manufacturing method) is described. Referring to 20(a) until 20(s) An example of a method of forming holes by electrolysis (the second manufacturing method) is described. Referring to 21(a) until 21(f) Another example of a method of forming holes by electrolysis (the third manufacturing method) is described.

- First manufacturing process -

The method of making a vapor deposition mask, which refers to 5 mask section 32 described, and the method for producing a vapor deposition mask, which is described with reference to 6 Mask portion 32 described include substantially identical processes except for the step of etching a substrate 32K. The following description focuses primarily on the process for producing a vapor deposition mask following the in 5 mask section 32 shown. The overlapping steps in the process for producing a vapor deposition mask that corresponds to the in 6 mask portion 32 shown are not described.

In the in 19(a) until 19(h) In the example shown of a method for producing a vapor deposition mask, a substrate 32K is first prepared ( 19(a) ). The substrate 32K is the vapor deposition mask substrate 1, which is to be processed as the mask plate 323 and, in addition to the vapor deposition mask substrate 1, preferably has a carrier SP which carries the vapor deposition mask substrate 1. The first surface 321 of the substrate 32K (the bottom in 19(a) until 19(h) ) corresponds to the first surface 1Sa described above, and the second surface 322 of the substrate 32K (the top in 19(a) until 19(h) ) corresponds to the second surface 1Sb described above.

A resist layer PR is formed on the second surface 322 of the prepared substrate 32K ( 19(b) ), and the resist layer PR is subjected to exposure and development so that a resist mask RM is formed on the second surface 322 ( 19(c) ). Holes 32H are then formed in the substrate 32K by wet etching from the second surface 322 using the resist mask RM ( 19(d) ).

In this step, second openings H2 at which wet etching begins are formed in the second surface 322, and first openings H1 smaller than the second openings are formed in the first surface 321, which is subjected to wet etching after the second surface 322 H2 are. The resist mask RM is then removed from the second surface 322, leaving the mask portion 32 described above ( 19(e) ). Finally, the outer edge portions 32E of the second surface 322 are bonded to the inner edge portions 31E of a frame portion 31, and the carrier SP is removed from the mask portion 32 to complete the vapor deposition mask 30 ( 19(f) ) until 19(h) ).

In the process for producing a vapor deposition mask that in 6 32, the above-described steps are performed on the surface of a substrate 32K corresponding to the first surface 321 to form small holes 32SH. This substrate 32K does not have a carrier SP. The small holes 32SH are then filled with a material such as a resist to protect the small holes 32SH. Then, on the surface of the substrate 32K corresponding to the second surface 322, the above-described steps are performed, thereby forming a mask portion 32.

This in 19(f) Example shown uses resistance welding to connect the outer edge portions 32E of the second surface 322 to the inner edge portions 31E of the frame portion 31. This method forms a plurality of holes SPH in an insulating carrier SP. The holes SPH are formed in the portions of the carrier SP facing the portions that become the connecting portions 32BN. Then, the connection portions 32BN are separately formed by energizing through the holes SPH. This welds the outer edge portions 32E to the inner edge portions 31E.

This in 19(g) The example shown uses laser welding to connect the outer edge portions 32E of the second surface 322 to the inner edge portions 31E of the frame portion 31. This method uses a transparent substrate SP and irradiates laser light L through the substrate SP to the portions that become the connecting portions 32BN. Separate connecting portions 32BN are formed by intermittently applying laser light L around the outer edge portion 32E. Alternatively, a continuous connection portion 32BN is formed along the entire circumference of the outer edge portion 32E by continuously applying laser light L around the outer edge portions 32E. This welds the outer edge portions 32E to the inner edge portions 31E.

This in 19(h) The example shown uses ultrasonic welding to connect the outer edge portions 32E of the second surface 322 to the inner edge portions 31E of the frame portion 31. This method applies ultrasonic waves to the portions that become the connecting portions 32BN, with the outer edge portions 32E and the inner edge portions 31E held together by clamps CP or other means. The element to which the ultrasonic waves are directly applied may be the frame portion 31 or the mask portion 32. The method using ultrasonic welding leaves indentations of the terminals CP in the frame portion 31 and the beam SP.

In the connection process described above, melting or welding can occur while a voltage is acting on the mask portion 32 towards the outside of the mask portion 32. If the wearer SP wears the mask portion 32 while a tension is acting on the mask portion 32 towards the outside of the mask portion 32, the application of tension to the mask portion 32 can be omitted.

- Second manufacturing process -

In addition to the first manufacturing process, the vapor deposition masks can be used with reference to 7 and 8th have been described, can be prepared by another example given in 20(a) until 20(s) is shown.

This in 20(a) until 20(s) The example shown first forms a resist layer PR on an electrode surface EPS, which is a surface of an electrode EP used for electrolysis (see 20(a) ). Then, the resist layer PR is subjected to exposure and development so that a resist mask RM is formed on the electrode surface EPS (see 20(b) ). The resist mask RM has the shape of an inverted cone in a cross section perpendicular to the electrode surface EPS blunt on. The cross-sectional area of each shape along the electrode surface EPS increases away from the electrode surface EPS. Then, using the electrode surface EPS having the resist mask RM, electrolysis is performed and a mask portion 32 is formed over the area on the electrode surface EPS other than the resist mask RM ( 20(c) ).

The mask portion 32 is formed in the space not occupied by the resist mask RM in this step. Accordingly, the mask portion 32 has holes shaped according to the shape of the resist mask RM. Self-aligned holes 32A are thus formed in the mask portion 32. The surface in contact with the electrode surface EPS functions as the first surface 321 having the first openings H1, and the outermost surface having the second openings H2 larger than the first openings H1 functions as the second surface 322.

Then, from the electrode surface EPS, only the resist mask RM is removed, leaving holes 32H, which are cavities extending from the first openings H1 to the second openings H2 (see 20(d) ). Finally, the bonding surface 311 of the inner edge portion 31E is bonded to the outer edge portion 32E of the second surface 322 having the second openings H2, and then voltage is applied to the frame portion 31 to peel the mask portion 32 from the electrode surface EPS. In this way, the vapor deposition mask 30 is manufactured, in which the mask section 32 is connected to the frame section 31 ( 20(s) ).

In the second manufacturing method, the mask portion 32 is formed without etching the evaporation mask substrate 1. When the outer edge portion 32E satisfies condition 1, where the direction along one side of the mask portion 32 is the width direction, the positional accuracy in joining between the frame portion 31 and the mask portion 32 and the bonding strength are increased.

- Third manufacturing process -

In addition to the first manufacturing process, the vapor deposition masks can be used with reference to 7 and 8th have been described, can be prepared by another example given in 21(a) until 21(f) is shown.

This in 21(a) until 21(f) The example shown first forms a resist layer PR on an electrode surface EPS, which is used for electrolysis (see 21(a) ). Then, the resist layer PR is subjected to exposure and development so that a resist mask RM is formed on the electrode surface EPS (see 21(b) ). The resist mask RM has the shape of a truncated cone in a cross section perpendicular to the electrode surface EPS. The cross-sectional area of each shape along the electrode surface EPS decreases away from the electrode surface EPS. Then, using the electrode surface EPS having the resist mask RM, electrolysis is performed and a mask portion 32 is formed over the area on the electrode surface EPS other than the resist mask RM ( 21(c) ).

In this step, the mask portion 32 is formed in the space not occupied by the resist mask RM. Accordingly, the mask portion 32 has holes shaped according to the shape of the resist mask RM. Self-aligned holes 32H are thus formed in the mask portion 32. The surface in contact with the electrode surface EPS functions as the second surface 322, which has the second openings H2, and the outermost surface, which has the first openings H1 smaller than the second openings H2, functions as the first surface 321.

Then, from the electrode surface EPS, only the resist mask RM is removed, leaving holes 32H, which are cavities extending from the first openings H1 to the second openings H2 (see 21(d) ). An intermediate transfer substrate TM is bonded to the first surface 321 having the first openings H1, and then voltage is applied to the intermediate transfer substrate TM to peel the mask portion 32 from the electrode surface EPS. This separates the second surface 322 from the electrode surface EPS, with the mask portion 32 connected to the intermediate transfer substrate TM ( 21(e) ). Finally, the bonding surface 311 of the inner edge portion 31E is bonded to the outer edge portion 32E of the second surface 322, and then the intermediate transfer substrate TM is removed from the mask portion 32. In this way it will the vapor deposition mask 30 is produced, in which the mask section 32 is connected to the frame section 31 ( 21(f) ).

In the third manufacturing method, the mask portion 32 is formed without etching the evaporation mask substrate material 1. When the outer edge portion 32E satisfies condition 1, where the direction along one side of the mask portion 32 is the width direction, the positional accuracy in joining between the frame portion 31 and the mask portion 32 and the bonding strength are increased.

In the method of manufacturing a display device using the above-described evaporation mask 30, the mask device 10 on which the evaporation mask 30 is mounted is placed in the vacuum chamber of the evaporation device. The mask device 10 is attached such that the first surface 321 faces the vapor deposition target, such as a glass substrate, and the second surface 322 faces the vapor deposition source. Then the vapor deposition target is brought into the vacuum chamber of the vapor deposition device and the vapor deposition material is sublimated from the vapor deposition source. This forms, on the vapor deposition target facing the first opening H1, a pattern shaped corresponding to the first opening H1. The vapor deposition material may be, for example, an organic light-emitting material for forming pixels of a display device or a pixel electrode for forming a pixel circuit of a display device.

- Examples -

With reference to 22 Examples will now be described.

A base material 1a made of Invar was subjected to a rolling step to form a metal foil. The metal foil was subjected to a slitting step in which the metal foil was cut into sections of the desired dimension in the width direction DW to form a rolled material 1b. The rolled material 1b was annealed to form a vapor deposition mask substrate 1 according to Example 1, which had a length in the width direction DW of 500 mm and a thickness of 20 μm.

Furthermore, except that the rotation speed and pressing force of the rollers 51 and 52 were changed from those in Example 1, under the same conditions as in Example 1, a vapor deposition mask substrate 1 according to Example 2 having a length in the width direction DW of 500 mm was obtained and had a thickness of 20 µm.

Except that the pressing force between the rollers 51 and 52 was changed from that in Example 1, under the same conditions as in Example 1, the vapor deposition mask substrate 1 according to Example 3 was obtained, which had a length in the width direction DW of 500 mm and a Thickness of 50 µm.

Further, except that the number of rollers 51 and 52 was changed from that in Example 1, a vapor deposition mask substrate 1 according to Example 4 having a length in the width direction DW of 500 mm and a thickness of 20 μm was obtained.

Subsequently, except that the number and temperature of the rollers 51 and 52 were changed from those in Examples 1 and 4, a vapor deposition mask substrate 1 according to Comparative Example 1 having a length in the width direction DW was obtained under the same conditions as in Example 1 of 500 mm and a thickness of 20 µm.

In addition, except that the number and pressing force of the rollers 51 and 52 were changed from those in Examples 1 and 3, under the same conditions as in Example 1, a vapor deposition mask substrate 1 according to Comparative Example 2 having a length in the width direction was obtained DW of 500 mm and a thickness of 20 µm.

Further, except that the number and pressing force of the rollers 51 and 52 were changed from those in Example 1, under the same conditions as in Example 1, a vapor deposition mask substrate 1 according to Comparative Example 3 having a length in the width direction of 500 was obtained mm and a thickness of 20 µm.

Referring to 22 A measurement substrate 2M having a length in the longitudinal direction DL of 700 mm was cut out from the vapor deposition mask substrate 1 of each of Examples and Comparative Examples. Then, the steepnesses in the width direction DW of each of the obtained measurement substrates 2M were measured over the entire measuring range ZL. The measurement conditions of the slopes in the width direction DW were as follows.
Measuring equipment: CNC image measuring system VMR-6555 manufactured by Nikon Corporation
Length in the longitudinal direction DL of the measuring range ZL: 500 mm (unit length)
Length in the longitudinal direction DL of the non-measuring area ZE: 100 mm
Measuring interval in the longitudinal direction DL: 20 mm
Measuring interval in the width direction DW: 20 mm

In order to exclude the wavy shape added in the slitting cut, the measurement in the width direction was made for the area of 480 mm in the width direction DW, which excluded the areas of 10 mm from the edges in the width direction DW. In detail, the measurement was carried out on 26 lines each, which were arranged in the longitudinal direction DL, at 25 points along the width direction DW. At each of the measurement intervals in each of the examples and comparative examples, the longitudinal direction DL is the direction in which the base material 1a is stretched by rolling.

Table 1 shows the measurement results of the first slope, the average of the second slope, the maximum value of the wave amounts and the average of the wave amounts of each of Examples 1 to 4 and Comparative Examples 1 to 3.

Table 1 shows that the first slope of Example 1 was 0.43%, indicating that Example 1 satisfied Condition 1. Of the twenty-six lines in Example 1, four lines each had a minimum unit steepness value of 0% and were without a noticeable wave in the width direction DW. The average of the second slopes was 0.20% in example 1, which fulfills condition 2. The standard deviation σ of the second slopes was 0.12%. The maximum value of the wave quantities in example 1 was four, which fulfills condition 3. Furthermore, the mean value of the wave quantities in Example 1 was one, which satisfies condition 4.

Example 2 had an initial slope of 0.29%, which satisfies condition 1. Among the twenty-six lines in Example 2, five lines each had a minimum value of unit slopes of 0% and were without a noticeable wave in the width direction DW. The average of the second slopes was 0.12% in example 2, which fulfills condition 2. The standard deviation σ of the second slopes was 0.09%. The maximum value of the wave quantities in example 2 was three, which fulfills condition 3. Furthermore, the mean value of the wave quantities in Example 2 was one, which satisfies condition 4.

Example 3 had an initial slope of 0.37%, which satisfies condition 1. Among the twenty-six lines in Example 3, seven lines each had a minimum unit slope value of 0% and were without a noticeable wave in the width direction DW. The average of the second slopes was 0.11% in example 3, which fulfills condition 2. The standard deviation σ of the second slopes was 0.12%. The maximum value of the wave quantities in example 3 was three, which fulfills condition 3. Furthermore, the mean value of the wave quantities in Example 3 was one, which satisfies condition 4.

Example 4 had an initial slope of 0.44%, which satisfies condition 1. Among the twenty-six lines in Example 4, one line had a minimum value of unit slopes of 0% and was without a noticeable wave in the width direction DW. The average of the second slopes in example 4 was 0.22%, which fulfills condition 2. The standard deviation σ of the second slopes was 0.11%. The maximum value of the wave quantities in example 4 was five, which is why it failed to fulfill condition 3. Furthermore, the mean value of the wave quantities in Example 4 was two, which satisfies condition 4.

Comparative Example 1 had a first slope of 0.90%, which is why it failed to satisfy Condition 1. The minimum value of the unit slopes in Comparative Example 1 was 0.11%. The average of the second slopes in Comparative Example 1 was 0.33%, which is why it failed to fulfill condition 2. The standard deviation σ of the second slopes was 0.18%. The maximum value of the wave quantities in Comparative Example 1 was eight, which is why it failed to fulfill condition 3. Furthermore, the average value of the wave amounts in Comparative Example 1 was five, which is why it failed to satisfy Condition 4. The minimum value of the wave quantities in Comparative Example 1 was three.

Comparative Example 2 had a first slope of 1.39%, which is why it failed to meet condition 1. The minimum value of the unit slopes in Comparative Example 2 was 0.06%. The average of the second slopes in Comparative Example 2 was 0.28%, which is why it failed to fulfill condition 2. The standard deviation σ of the second slopes was 0.29%. The maximum value of the wave quantities in Comparative Example 2 was five, which is why it failed to fulfill condition 3. Furthermore, the average value of the wave amounts in Comparative Example 2 was two, which satisfies Condition 4. The minimum value of the wave quantities in Comparative Example 2 was one.

Comparative Example 3 had a first slope of 0.58%, which is why it failed to satisfy Condition 1. The minimum value of the unit slopes in Comparative Example 3 was 0.06%. The average of the second slopes in Comparative Example 3 was 0.31%, which is why it failed to fulfill condition 2. The standard deviation σ of the second slopes was 0.14%. The maximum value of the wave quantities in Comparative Example 3 was six, which is why it failed to satisfy Condition 3. Furthermore, the average value of the wave amounts in Comparative Example 3 was four, which is why it failed to satisfy Condition 4. The minimum value of the wave quantities in Comparative Example 3 was one. Table 1 example 1 Example 2 Example 3 Example 4 Comparative example 1 Comparative example 2 Comparative example 3 First slope (%) 0.43 0.29 0.37 0.44 0.90 1.39 0.58 Average second slopes (%) 0.20 0.12 0.11 0.22 0.33 0.28 0.31 Maximum value wave quantities (quantity) 4 3 3 5 8th 5 6 Average wave quantities (amount) 1 1 1 2 5 2 4 Fluctuation ◯ ◯ ◯ ◯ × × ×

- Pattern accuracy -

On the first surface 1Sa of the vapor deposition mask substrate 1 of each of Examples 1 to 4 and Comparative Examples 1 to 3, a first TFR 2 having a thickness of 10 μm was attached. Each first TFR 2 was subjected to an exposure step in which the first TFR 2 was exposed while in contact with an exposure mask and a development step. This formed through holes 2a having a diameter of 30 μm in the first TFR 2 in a grid pattern. Then, the first surface 1Sa was etched using the first TFR 2 as a mask, so that holes 32H were formed in the evaporation mask substrate 1 in a grid pattern. In the width direction DW of the vapor deposition mask substrate 1, the diameter of the opening of each hole 32H was measured. Table 1 shows the variations in the diameter of the openings of the holes 32H in the width direction DW. In Table 1, the levels at which the difference between the maximum value and the minimum value of the opening diameter of the holes 32H was less than or equal to 2.0 µm are marked with “O”, and the levels at which the difference between the maximum value and the minimum value of the opening diameter was greater than 2.0 µm are marked with “x”.

As shown in Table 1, the variations in the diameter of the openings of Examples 1 to 4 were less than or equal to 2.0 μm. Among Examples 1 to 4, Examples 1 to 3 had smaller variations in the diameter of the openings than Example 4. Furthermore, the variations in the diameter of the openings of Comparative Examples 1 to 3 were larger than 2.0 μm. The comparison between Examples 1 to 4 and Comparative Examples 1 to 3 shows that a structure in which the first steepness is less than or equal to 0.5%, that is, a structure which satisfies Condition 1, has a variation in the diameter of the openings limited. In addition, a structure in which the average of the second slopes is less than or equal to 0.25%, that is, a structure that satisfies condition 2, limits the variation in the diameter of the openings.

The comparison between Examples 1 to 3 and Example 4 shows that a structure in which the quantities of waves per unit length are less than or equal to four, i.e. a structure that satisfies condition 3, further limits the fluctuations in the diameter of the openings. In addition, a structure in which the average value of the amounts of waves per unit length is less than or equal to two, that is, a structure that satisfies condition 4, further limits the variation in the diameter of the openings.

1. (1) Die höhere Genauigkeit der Form und Größe der Löcher im Maskenabschnitt 32 erhöht die Genauigkeit des Musters, das durch Aufdampfen ausgebildet wird. Das Verfahren zum Belichten des Resists ist nicht auf ein Verfahren beschränkt, das die Belichtungsmaske mit dem Resist in Kontakt bringt. Die Belichtung kann erfolgen, ohne den Resist mit der Belichtungsmaske in Kontakt zu bringen. Wird der Resist mit der Belichtungsmaske in Kontakt gebracht, presst dies das Aufdampfmaskensubstrat auf die Oberfläche der Belichtungsmaske. Dies begrenzt eine Verringerung der Belichtungsgenauigkeit, die andernfalls aufgrund der gewellten Form des Aufdampfmaskensubstrats auftreten würde. Die Genauigkeit in dem Schritt, in dem die Oberfläche mit Flüssigkeit bearbeitet wird, wird ungeachtet des Belichtungsverfahrens erhöht, wodurch die Genauigkeit des Musters erhöht wird, das durch Aufdampfen ausgebildet wird.
2. (2) Die Oberfläche des Aufdampfmaskensubstrats 1 hat eine begrenzte Schwankung infolge einer Entwicklung mittels einer Entwicklungslösung und infolge eines Reinigens mittels einer Reinigungslösung. Dies erhöht die Gleichmäßigkeit der Form und Größe der ersten und zweiten Durchgangslöcher 2a und 3a in der Oberfläche des Aufdampfmaskensubstrats 1, die durch den Belichtungsschritt und den Entwicklungsschritt ausgebildet werden.
3. (3) Die Oberfläche des Aufdampfmaskensubstrats 1 hat eine begrenzte Schwankung infolge eines Ätzens mittels eines Ätzmittels und infolge eines Reinigens des Ätzmittels mittels einer Reinigungslösung. Die Oberfläche des Aufdampfmaskensubstrats 1 hat eine begrenzte Schwankung infolge eines Strippens der Resistschicht mittels einer Stripplösung und infolge eines Reinigens der Stripplösung mittels einer Reinigungslösung. Dies erhöht die Gleichmäßigkeit der Form und Größe der kleinen Löcher 32SH und der großen Löcher 32LH in der Oberfläche des Aufdampfmaskensubstrats 1.
4. (4) Die Menge der Löcher 32H, die in einem Rahmenabschnitt 31 vorausgesetzt wird, ist in drei Maskenabschnitte 32 aufgeteilt. Die Gesamtfläche der Maskenabschnitte 32, die in einem Rahmenabschnitt 31 vorausgesetzt wird, ist zum Beispiel in drei Maskenabschnitte 32 aufgeteilt. Eine teilweise Verformung eines Maskenabschnitts 32 in einem Rahmenabschnitt 31 erfordert somit keinen Austausch aller Maskenabschnitte 32 in dem Rahmenabschnitt 31. Verglichen mit einem Aufbau, in dem ein Rahmenabschnitt 31 nur einen Maskenabschnitt 32 aufweist, kann die Größe eines neuen Maskenabschnitts 32 beim Austausch des verformten Maskenabschnitts 32 auf etwa ein Drittel verringert werden.
5. (5) Die Steilheiten von jedem Messsubstrat 2M wurden gemessen, während die Abschnitte an den zwei Kanten in der Längsrichtung DL des Messsubstrats 2M und die Abschnitte an den zwei Kanten in der Breitenrichtung DW des Messsubstrats 2M als Nichtmessbereiche von der Messung der Steilheiten ausgeschlossen wurden. Jeder Nichtmessbereich ist der Bereich, der eine gewellte Form haben kann, die ausgebildet wird, wenn das Aufdampfmaskensubstrat 1 geschnitten wird, und er unterscheidet sich somit von der gewellten Form des anderen Abschnitts des Aufdampfmaskensubstrats 1. Wird der Nichtmessbereich als solches von der Messung ausgeschlossen, erhöht dies die Messgenauigkeit der Steilheiten.

The embodiment described above has the following advantages.

1. (1) The higher precision of the shape and size of the holes in the mask portion 32 increases the precision of the pattern formed by vapor deposition. The method for exposing the resist is not limited to a method that brings the exposure mask into contact with the resist. Exposure can occur without bringing the resist into contact with the exposure mask. When the resist is brought into contact with the exposure mask, this presses the vapor deposition mask substrate onto the surface of the exposure mask. This limits a reduction in exposure accuracy that would otherwise occur due to the corrugated shape of the deposition mask substrate. The accuracy in the step of processing the surface with liquid is increased regardless of the exposure method, thereby increasing the accuracy of the pattern formed by vapor deposition.
2. (2) The surface of the vapor deposition mask substrate 1 has a limited fluctuation due to development by a developing solution and cleaning by a cleaning solution. This increases the uniformity of the shape and size of the first and second through holes 2a and 3a in the surface of the vapor deposition mask substrate 1 formed by the exposure step and the development step.
3. (3) The surface of the vapor deposition mask substrate 1 has a limited fluctuation due to etching by an etchant and due to cleaning of the etchant by a cleaning solution. The surface of the vapor deposition mask substrate 1 has a limited fluctuation due to stripping the resist layer using a stripping solution and cleaning the stripping solution using a cleaning solution. This increases the uniformity of the shape and size of the small holes 32SH and the large holes 32LH in the surface of the vapor deposition mask substrate 1.
4. (4) The amount of holes 32H required in one frame portion 31 is divided into three mask portions 32. The total area of the mask sections 32, which is assumed in a frame section 31, is divided into three mask sections 32, for example. Partial deformation of a mask portion 32 in a frame portion 31 thus does not require replacement of all mask portions 32 in the frame portion 31. Compared with a structure in which a frame portion 31 has only one mask portion 32, the size of a new mask portion 32 can be increased when replacing the deformed mask portion 32 can be reduced to about a third.
5. (5) The slopes of each measurement substrate 2M were measured while excluding the portions at the two edges in the length direction DL of the measurement substrate 2M and the portions at the two edges in the width direction DW of the measurement substrate 2M as non-measurement areas from the measurement of the slopes. Each non-measurement area is the area which may have a wavy shape formed when the vapor mask substrate 1 is cut, and is thus different from the wavy shape of the other portion of the vapor mask substrate 1. If the non-measurement area as such is excluded from the measurement, This increases the measurement accuracy of the slopes.

The exemplary embodiment described above can be modified as follows.

- Method for producing a vapor deposition mask substrate -

In the rolling step, a rolling mill having a plurality of pairs of rolls that roll the base material 1a can be used. The method using a plurality of roller pairs increases flexibility in control parameters to satisfy conditions 1 to 4.

Furthermore, instead of annealing the rolled material 1b while extending in the longitudinal direction DL, the rolled material 1b may be annealed in a state in which it is wound around the core C in a roll. When annealing is performed with the rolled material 1b wound in a roll, the evaporation mask substrate 1 may show a tendency to warp according to the diameter of the roll. Depending on the material of the vapor deposition mask substrate 1 and the diameter of the um Therefore, since the roll wound around the core C, it may be preferable that the rolled material 1b is annealed while it is elongated.

Further, the rolling step and the annealing step may be repeated alternately to produce a vapor deposition mask substrate 1.

The vapor deposition mask substrate 1 prepared by electrolysis and the vapor deposition mask substrate 1 prepared by rolling may be further thinned by chemical or electrical polishing. The conditions such as the composition and supply method of the polishing solution can be adjusted so that conditions 1 to 4 are satisfied after polishing. In order to reduce the internal stress, the polished vapor deposition mask substrate 1 can be subjected to an annealing step.

Although several embodiments have been described herein, it will be apparent to those skilled in the art that the present invention may be embodied in various specific forms without departing from the spirit of the invention. The invention is not limited to the details given herein, but may be modified within the scope and equivalence of the appended claims.

Claims (8)

A vapor deposition mask substrate (1), which is a metal foil having the shape of a strip and designed to be etched to have a plurality of holes (32H) and used to make a vapor deposition mask, wherein the metal foil has a longitudinal direction (DL) and a width direction (DW), the metal foil has shapes in the width direction (DW) which are taken from different positions in the longitudinal direction (DL) of the metal foil and are different from each other, each shape has waves that repeat in the width direction (DW), each wave has a valley at each of two ends of the wave, each wave has a length which is a length of a straight line in the latitudinal direction (DW) connecting one of the valleys of the wave to the other valley, a percentage of a height of each wave based on the length of the wave is a unit steepness, the metal foil has a unit length in the longitudinal direction (DL) of 500 mm, a maximum value of the unit slopes of the metal foil for the unit length is a first slope and the first slope is less than or equal to 0.5%. vapor deposition mask substrate (1). Claim 1 , where at each position in the longitudinal direction (DL), a maximum value of the unit steepnesses of all waves in the width direction (DW) is a second steepness, and an average of the second steepnesses of the metal foil for the unit length is less than or equal to 0.25%. vapor deposition mask substrate (1). Claim 1 or 2 , where at each position in the length direction (DL), a number of waves in the width direction (DW) is a quantity of waves at that position, and a maximum value of the quantity of waves of the metal foil for the unit length is less than or equal to four. Vapor deposition mask substrate (1) according to one of Claims 1 until 3 , where at each position in the length direction (DL), a number of waves in the width direction (DW) is a quantity of waves at that position, and an average of the quantity of waves of the metal foil for the unit length is less than or equal to two. A method of manufacturing a vapor deposition mask substrate (1) which is a metal foil having the shape of a strip and designed to be etched to have a plurality of holes (32H) and used to fabricate a vapor deposition mask, wherein the method comprises: obtaining the metal foil by rolling a base material (1a), the metal foil having a longitudinal direction (DL) and a width direction (DW), the metal foil having shapes in the width direction (DW) located at different positions in the longitudinal direction (DL) of the metal foil and are different from each other, each shape has waves that repeat in the width direction (DW), each wave has a valley at each of two ends of the wave, each wave has a length, which is a length of a straight line in the width direction (DW) connecting one of the valleys of the wave to the other valley, a percentage of a height of each wave relative to the length of the wave is a unit steepness, the metal foil one unit length in the longitudinal direction (DL) of 500 mm, a maximum value of the unit steepness of the metal foil for the unit length is a first steepness, and the base material (1a) is rolled such that the first steepness is less than or equal to 0.5%. A method for producing a vapor deposition mask, the method comprising: forming a resist layer on a metal foil having the shape of a stripe; and forming a plurality of holes (32H) in the metal foil by etching using the resist layer as a mask to form a mask portion (32), wherein the metal foil has a longitudinal direction (DL) and a width direction (DW), the metal foil has shapes in the width direction (DW) which are taken from different positions in the longitudinal direction (DL) of the metal foil and are different from each other, each shape has waves that repeat in the width direction (DW), each wave has a valley at each of two ends of the wave, each wave has a length which is a length of a straight line in the latitudinal direction (DW) connecting one of the valleys of the wave to the other valley, a percentage of a height of each wave based on the length of the wave is a unit steepness, the metal foil has a unit length in the longitudinal direction (DL) of 500 mm, a maximum value of the unit slopes of the metal foil for the unit length is a first slope and the first slope is less than or equal to 0.5%. Method for producing a vapor deposition mask Claim 6 , wherein the mask portion is one of a plurality of mask portions (32), forming the mask portion includes forming the mask portions (32) in the single metal foil, the mask portions (32) each having a separate side surface containing some of the holes (32H) and the method further comprises connecting the side surfaces of the mask sections (32) to a single frame section (31) such that the single frame section (31) surrounds the holes (32H) of each mask section (32). A method of manufacturing a display device, comprising: preparing a vapor deposition mask by the method of manufacturing a vapor deposition mask according to Claim 6 or 7 was produced; and forming a pattern by vapor deposition using the vapor deposition mask.

Images